1. Technical Field
The present invention relates generally to display devices and, more particularly, to a thin film transistor, a method of manufacturing the thin film transistor, and an organic light emitting device including the the thin film transistor.
2. Related Art
In display devices generally, a plurality of pixels are arranged in a matrix form, and images are displayed by controlling the light intensity of each pixel according to given luminance information. Among the various types of display devices, an organic light emitting display is a self-emission type and has low power consumption, a wide viewing angle, and a fast pixel response speed. Accordingly, the organic light emitting display is receiving attention as a next-generation display device to surpass the liquid crystal display (LCD).
For the organic light emitting display device, each pixel includes a light-emitting device, a driving transistor for driving the light emitting device, and a switching transistor for applying a data voltage to the driving transistor. The driving transistor generally is a thin film transistor (TFT) that may be classified, for example, as a poly-crystalline silicon (also referred to as “polysilicon”) thin film transistor or an amorphous silicon thin film transistor, according to the kind of active layer in the thin film transistor.
For polysilicon thin film transistors, a polysilicon layer is formed, an ohmic contact layer is formed thereon, and a crystallinity process is generally executed. In the crystallinity process of this structure, the impurity of the ohmic contact layer is diffused into the semiconductor, and is present in the channel region of the semiconductor. This impurity generates a leakage current, thereby deteriorating the electrical characteristics of the thin film transistor and leading to the appearance of a stain when manufacturing the display device including the thin film transistor.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.